The present invention relates to vehicle guidance control systems. More particularly, the present invention relates to a guidance control system that includes a light bar assembly.
Tractors and other vehicles used in farming operations must be operated precisely to obtain uniform rows during planting and to harvest crops efficiently. Typically, tractors used for planting rows of crops are operated manually by an operator who drives the tractor along each row to be planted. The operator must be very careful in order to get uniform rows of planted crops. It is difficult for an operator of a tractor to maintain precise positioning of the tractor relative to rows which have already been planted.
In an attempt to make the job of planting easier on the operator, manufacturers of tractors and other vehicles have recently attempted to use automated guidance control systems. These guidance control systems typically include a Global Positioning System (GPS) for determining position.
One particular helpful use of GPS is in guiding a vehicle to move on a predetermined path for planting crops. This predetermined path runs through consecutively placed rows. Specifically, the center line of this predetermined path coincides with the center lines of these rows.
In one prior art approach, a guidance control system is used that includes a visible display. The operator of the vehicle manually directs the vehicle in accordance with the visible display to guide a vehicle along a predetermined path. However, the predetermined path often lies over terrain that is tilted. In this scenario, the tilted surface introduces at least two complications (errors) in guiding the vehicle.
The first error caused by the tilted surface is the tilting of the GPS antenna. That is, when traveling over a tilted surface, the vehicle itself is not directly over the center of a row, even though the tip of the GPS antenna is directly over the center of a row. Thus, the vehicle is not properly positioned. As a result, by following the predetermined path on the tilted surface, the vehicle actually travels off of the center line of the row.
The second error caused by the tilted surface is the shortening of xe2x80x9cvertically viewedxe2x80x9d path width. Specifically, the vertically viewed path width refers to the path""s width as viewed vertically straight down from a high vantage point. On a flat surface, the vertically viewed path width for a vehicle traveling along a predetermined path coincides with the width of each row. However, on a surface tilting in a perpendicular direction to a path (i.e., lateral tilting), the path""s vertically viewed path width does not coincide with the width of each row. Thus, on the tilted surface, the vehicle is being guided to travel on the predetermined path that deviates from the desired path width.
In one recent prior art guidance control system, a tilt sensor is used to compensate for the above two tilting errors. The tilt sensor is typically contained within a separate housing that is coupled to a control unit via a cable. The control unit is coupled via cables to a visual display and a GPS.
However, prior art systems that include a tilt sensor that couples to a control unit require an extra serial port to accommodate the tilt sensor. In view of the need for competitive pricing, the serial port is costly to implement. Moreover, using cables to couple the tilt sensor to the control unit exposes the entire guidance control system to extra electrical noise. This electrical noise can be especially problematic for the intended outdoor use of the guidance control system for agricultural purposes.
In another recent prior art guidance control system, a tilt sensor is also used to compensate for the above two tilting errors. In particular, the tilt sensor is integrated directly inside of a control unit. The control unit in turn is coupled via cable to a visual display and is coupled via a cable to a GPS.
By integrating the tilt sensor with the control unit, this prior art approach avoids the need to include extra serial ports and cables to accommodate a stand alone tilt sensor. However, integrating the tilt sensor with the control unit requires modification of the control unit that is costly to implement. In addition, for users who have already purchased a control unit not fitted with any tilt sensor, it is costly to buy a new control unit solely for the purpose of getting the benefits provided by the tilt sensor. For the above reasons, these prior art guidance control systems fitted with tilt sensors are typically expensive and difficult to implement.
Thus, a need exists for incorporating a tilt sensor into a guidance control system that does not require creation of extra serial port to accommodate the tilt sensor. Moreover, a need exists for incorporating a tilt sensor into a guidance control system that does not require the tilt sensor to couple to the control unit using a dedicated cable that introduces extra electric noise. Furthermore, a need exists for incorporating a tilt sensor into a guidance control system that does not require costly modification of the control unit. Finally, a need exists for incorporating a tilt sensor into a guidance control system that does not require a user to replace an existing control unit.
The present invention is drawn to a light bar assembly for guiding the movement of a vehicle. The light bar assembly includes a tilt sensor for accurately guiding the movement of the vehicle on a tilted surface. In particular, when the vehicle travels on the tilted surface, the present invention compensates for the error caused by the tilt of a GPS antenna coupled to the vehicle.
In one embodiment of the present invention, a light bar assembly is described for guiding a vehicle. The light bar assembly includes a light bar and a tilt sensor. The light bar assembly also includes a housing. The light bar is disposed in the housing and guides the movement of the vehicle. That is, the light bar indicates changes to the travel path of the vehicle. The operator then moves the vehicle in the indicated direction. The tilt sensor is also disposed in the housing. The tilt sensor measures the attitude of the vehicle. The attitude of the vehicle is taken into consideration for determining the travel path to be indicated while traveling over a tilted surface. Thus, notwithstanding the tilted surface, the vehicle being guided advantageously avoids deviating from the true path intended.
In another instance, the present invention is embodied as a guidance control system for controlling a vehicle""s movement. The guidance control system includes a Position Determination System (PDS). The guidance control system includes a light bar assembly. The light bar assembly includes a light bar and a tilt sensor. The PDS is adapted to determine the position of the vehicle. The light bar is adapted for guiding the vehicle to move on a path. The tilt sensor measures the attitude of the vehicle. The guidance control system also includes a control unit that is coupled to the light bar assembly. Specifically, using the lateral tilt angle of the vehicle as determined by the tilt sensor, the control unit indicates an adjusted travel path for the vehicle to compensate for errors caused by the tilted surface. Thus, notwithstanding the tilted surface, the vehicle being guided along the adjusted travel path advantageously avoids deviating from the true path intended.
As implemented in these embodiments, the present invention advantageously avoids fitting an extra serial port devoted to the tilt sensor, as is required in prior art systems that include a tilt sensor. Moreover, the present invention advantageously avoids the electric noise from coupling the tilt sensor to the control unit using a dedicated cable, as occurs in prior art systems that include a tilt sensor. In addition, the present invention advantageously avoids costly modification needed for internalizing the tilt sensor into the control unit. Moreover, the present invention advantageously offers a convenient and inexpensive upgrade for an existing system having no tilt sensor.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the various drawing figures.